This invention in general concerns a lift apparatus and drive therefor, and in particular it concerns a trash receptacle lift for use with a refuse-gathering vehicle, and a slim profile rotary motor which may be used to actuate such a lift.
In recent years, conventional residential trash cans which must be manually emptied into the back of a refuse-gathering vehicle have been increasingly replaced with a somewhat standardized trash receptacle which has wheels for ease of transportation by a resident between his or her house and curb side, and which is further adapted to be lifted and dumped with a power lift unit mounted on the refuse-gathering vehicle (i.e garbage truck). The construction and operation of various waste receptacle dumping mechanisms are known. See for example, Brown et al. (U.S. Pat. No. 3,804,277, issued Apr. 16, 1974); Shive (U.S. Pat. No. 3,894,642, issued July 15, 1975); and Wyman et al. (U.S. Pat. No. 4,479,751, issued Oct. 30, 1984), each of which generally disclose a movable carriage adapted for receipt of a receptacle thereon, the contents of which are to be dumped into a garbage truck. Each movable carriage is generally supported on arms which are actuated by various drive means, such as hydraulic actuators, for raising and substantially inverting the movable carriage so as to dump the receptacle contents into a garbage truck on which the lift unit is mounted. The disclosures of such patents are incorporated herein by reference.
While different companies, such as Zarn, Inc., of Reidsville, North Carolina, and Applied Plastics Company, also of North Carolina, market various lift units adapted for specific use with particular styles of receptacles, most of such receptacles have certain generally standard features. For example, many typical receptacles have a single axle with wheels on each end of such axle to permit the receptacle to be rolled about by the user. An extended handle bar or its equivalent permits ready manipulation and required tilting of the receptacle so that it may roll on its two wheels. The side of the receptacle opposite such handle bar typically has an engagement member located about 34 inches above ground level. By appropriate tilting of the receptacle as it is brought into position to be lifted, such engagement member may be hooked onto a fixed element of the lift apparatus movable carriage, so that the receptacle may be raised and inverted by the lift apparatus.
Obviously, such gravity-type engagement feature would, if used by itself, be defeated during inversion of the movable carriage. To prevent such occurrence, various movable engagement hooks are activated during dumping of the receptacle to engage it at an additional point thereon below the above-mentioned fixed element so as to retain the receptacle on the movable carriage while it is being inverted. The above-identified patents also each disclose examples of such engagement means and their operation during a receptacle dumping cycle.
While such types of lift devices and associated receptacles generally permit mechanized dumping (as opposed to manual), various drawbacks and inefficiencies persist. For example, such prior art receptacle dumping mechanisms typically tend to dump the contents of the receptacle only near the very back of the refuse-receiving opening of the garbage truck. A typical garbage truck has a large opening located at its rear to provide access to a relatively large trash container carried on the truck. A dumping apparatus as discussed above is usually mounted adjacent such opening, such as on a rear bumper of the truck. A built-in trash compactor is also present in the container for compacting refuse therein. If the contents of the receptacle are dumped only at the very back of such refuse-receiving opening (as is often the case), a compaction cycle (i.e. operation of the built-in compactor of the garbage truck) must be run after almost each successive receptacle dumping so as to push the dumped contents forward, i.e. away from the very rear of the garbage truck, to make room for the next dumping. Having to frequently repeat compacting cycles is very time consuming, since a garbage truck normally would include a great number of stops at relatively short intervals on its route, and also adds to wear and tear on the compactor equipment.
Another drawback of such prior art mechanized dumping devices is the sheer size of the unit itself. Many prior art dumping devices have a width (i.e. projection from the rear bumper of the garbage truck) in a range of about 16 to 20 inches. That range is without the trash receptacle mounted for dumping. A safety hazard is thus presented by structure which projects substantially from the rear of the vehicle, particularly since it cannot be seen by the driver of the truck.
Also, as an additional practical matter, garbage trucks outfitted with such prior art (relatively thick) dumping apparatuses for smaller residential trash receptacles cannot be simultaneously used for dumping larger commercial trash dumpsters. Such dumpsters are normally pivoted against pivot members mounted at the rear of the truck itself while being winched upward with a powered cable mounted at the top of the garbage truck. Such dual use of a garbage truck is normally not possible with the typical prior art residential receptacle dumping device because there is not sufficient clearance for the commercial dumpster to be pivoted on the truck-mounted pivot members around the prior art residential dumping devices due to their relatively thick width.
Additionally, some refuse-gathering vehicles have their refuse-receiving openings on the sides of the truck, rather than at their backs. Such side-loading vehicles typically cannot safely use such prior art dumping devices again because they generally extend too far from the side of the truck.